Resistance unit.



, UNITED sTATEs .PATENT OFFICE.

HARRY E. sTRATToN,oE CLEVELAND, OHIO; AssIGNOR To THE ELECTRIC CONTROLLER & MANUFACTURING COMPANY, OE CLEVELAND, OHIO, A CORPORATION OE OHIO;

REsIsTANCE UNIT.

specification if-Lettersratent. Patented Aug- 13, 1918,

Application mea November s, i915. serial No. 60,514.-

To all whom t may concern Be it known that I, HARRY F. STRATTON, a citizen of the. United States, residing at Cleveland, in the countyof Cuyahoga and State of Ohio, have invented new and .useful Improvements in Resistance Units, `of which the following is a specification.

This invention relates to electrical resistance for motor starting, heating, etc., and relates particularly to what is known as unittype resistance.

One well-known 4resistancel unit` is v made by winding afiat strip or'ribbon of resistance material into adisk -or flat' spiral', 4the convolutions thereof being insulated from each other. The convolutions of such a Aresistance become loose, and sometimes slip' over each other axially,`so that the unit becomes dished or conical in shape.

One object of mylinvention is to provide a resistance unit ofl the spiral disk form,

which retains its disk shape under all conditions of service. Another o bject is to pr ovide a spirally wound 4resistance unit 1n which the ends of the resistance'material are held without the aid of screws, n.sts, or other additional parts. e

Referring to the accompanying drawings, Figure 1 is an elevation of a complete resistance unit embodying the principles of my invention; Fig. 2, a cross-section taken on vthe line 2 of Fig. l; and Fig. 3, a fragmentary 4vview showing an elevation of the upper portion of Fig. 1, looking inthe direction of the arrow 3. A

On the drawing, I show the spool 1, preferably of iron, the outer ring 2, also preferably of iron, the strip of resistance ymaterial 3, and the strip of insulating material 4.

The spool 1 has the 4central opening 5, the parallel ends 6 and 7, and the peripheral rib 8 preferably V-shaped in cross-section.-v

riihis rib may be variously formed but Iprefer to form it by cutting an annular groove 19 out of the spool at each side o f the annular line which is to constitute the outermost portion of the rib. I have shown the rib 8 nearer the end 7 than the end 6 ,of the spool,

whereby the rim 9 left at the end 7 of the spoolisnarrower thanthenini 10 left at the-end 6. 11 is a slot out entirely through one side of the spool, preferably fromend to end.

The ring 2 has the hook 12 to receive a supporting rod, not shown. The sides 13,

iof the groove 15.

and M of the nook are parallel lie on the same planes,- respectively, as the ends 6 and 7 of the'spool. The inner wall of the to the shape of the rib 8. The ring is thickened at 16 near the hook 12 where it is provided with the slot 17 `open at one side', as

shown at 22', and having its wall nearestthe hook grooved to correspond to the groove 15,

vas shown at'18. AThe slot 17 extends' from ring 2 has the vgroove 15 which corresponds -the interior of the ring to the exterior thereof, the groove 18 being a continuation slot 11 in the spool, as shown at 20. The -str1p of resistance is also positioned in the slot 17. The spindle is then rotated approximately one revolution which' winds one layer ofthe resistance strip 3 on lthe spool 1. Then the insulating strip 4 is fed through the slot 17 along with the resistance strip 3 and' thereafter wound simultaneously around the spool with the resistance strip. The spool is continuously rotated,the two strips 3 and 1 being wound in a double spiral, one closely litting the other all the way outwardly from the end ofthe first convolution of the resistance strip. The winding of the strips 3 and 4 is continued until they compactly lill the entire space between the -spool and the ring; whereupon the strips are cut ofi' at the outer end of the s lot 17, no binding or clamping means being necessary.

The unit described may beused alone, or assembled side by side with 'similar units on rods, which extend through the bore 5 and hook 12- of each unit, in a manner well known.

By reason of .the interlocklng or equitant connections between the @consecutive 'layers of the strips 3 and f1 yandfof'the said layers with the said 'rib 8 and groove, 15, a unit, wound so that the consecutive ylayers fit tightly on eachother andfSQ-that' the inner and outerv pori-'tions are wedged ti htly on the rib 8 and irtthejgro've 15?, wi; not bemy resistance units strip, 'a spool on come dishe l,\even when jarred in a horizont-al position.

I claim 1. A resistance unit containing a splrallvwound insulated resistance strip, the convolutions thereotl resting one on another in an equitant manner and'thereby lneventing the convolutions from dishing.

2. A resistance unit Containing a spil-allywouncl insulated resistance strip, the convolutions thereof resting one on another in an equitant manner and thereby preventingvthe coiwolutions from dishing, a. spool in the center of the unit and a ring Within which theperiphery ot the wound strip is confined,

the inner surface ot' the ringulitting theshape' of the periphery ot the Wound strip to prevent its lateral movement 1n the ring.

3. In a. resistance unit, an insulatedresistance strip, a spool on which the strip is wound to foi-1n a flat spiral, and a continuous wound,` the strip being angular in cross-section and the spool and ring having the surfaces which contact with the strip shaped to lit the latter.

5. n' a resistance unit, an insulated ,resistance strlp, a spool on which the strip is Wound to form a flat spiral, and a ring Within which the strip is Wound, the spiral compaotly lling the ring,'the rictional engagement of the last convolution With the ring preventing the unwinding of the spiral, the strip being transversely reieXed, and the .ring having the surface which contacts with the strip shaped to lit the strip.

6. In a resistance unit, a spool, an inslb' lated resistance strip Wound spirally thereon,

y and a continuous ring Within. which the spiralis Wound, so coinpactly filling thering that frictional engagement between the last,

convolution and the ring prevents the un- 'winding' of the spiral.

T ln a resistance unit, a spool, an insulated resist-ance strip Wound spirally thereon,

anda continuous ring Within which the spiral 1s Wound, so compactly lling the ring that rietional engagelnentbetween the last convolution and the rin prevents the un- 'l winding of the spiral, t 'e ring having an .aperture through Which the strip is Wound.a 8. lin a reslstancevunit, a spool, any insulated resistance strip secured thereon, and

Wound spirally thereon, and a continuous ring Within which the spiral is Wound, `fill- ,ing'the ring so compactly that the rictional engagement between 'the' last convolution and the ring revente the unwinding of the spiral,;and t e 'ring and the spool being 'adapted by their engagement with the strip to serve as electrical terminals forthe unit.

. Signed at Cleveland, hiO, this 5th day of November 11915` HARRY ir. 'sree'riion 

